Universal shaft

ABSTRACT

Universal shaft includes two shaft portions having respective inner ends splined to one another so that the portions are nonrotatable though axially displaceable relative to one another, the surface material of at least one of the portions at the splined connection having relatively good antifriction and wearing properties, sealing means surrounding the splined portions and enclosing a lubricant-filled inner chamber for the splined connection, the sealing means including a sealing ring and a scraper ring located adjacent and coaxial to one another, the scraper ring having a scraping end facing outwardly, and a permanently lubricated swivel joint carried by each of the shaft portions at respective outer ends thereof.

Unite States Patent 3,367,142 2/l968 Groves et al 64/23 3,470,711 /1969Kayser i. 64/l7 3,504,936 4/1970 Brown et a]. 64/23 X Primary Examiner-Edvvard G. Favors AttarneysCurt M. Avery, Arthur E. Wilfond, Herbert L.

Lerner and Daniel J. Tick ing outwardly, and a permanently lubricatedswivel joint carried by each of the shaft portions at respective outerends thereof.

\lll i 72] Inventor Hans-Joachim Kleinschmidt Essen, Germany [21] Appl.No. 14,436 [22] Filed Feb. 26, 1970 Patented Jan. 11, 1972 [73] AssigneeGelenkwellenbau G.m.b.I-l.

Essen, Germany [32] Priority Feb. 28, 1969 [33] Germany [31] P 19 10284.2

[5 4] UNIVERSAL SHAFT 9 Claims, 1 Drawing Fig. [52] U.S. Cl 64/23 [51]Int. Cl r Fl6d 3/06 Field oi'Search 64/23, 17; 287/53; 277/207 [56]References Cited UNITED STATES PATENTS 2,239,192 4/1941 Cutting. 64/23 XUNIVERSAL SHAFT My invention relates to universal shaft and moreparticularly to such universal shaft which includes two shaft portionshaving respective inner ends splined to one another so that the shaftportions are axially displaceable but nonrotatable relative to oneanother, a contact seal for sealing a lubricant-filled inner chamber forthe splined connection, and a swivel joint carried by at least one ofthe shaft portions at the other end thereof.

It has been known also to coat load-transmitting tooth profiles or thelike with a suitable plastic material to provide relatively goodantifriction and wearing properties.

Furthermore, swivel joints which require no servicing throughout theirlifetime have been known heretofore.

It is an object of my invention to provide universal shaft whichrequires no maintenance throughout its serviceable lifetime and has arelatively great durability as compared to heretofore known universalshaft of this general type.

With the foregoing and other objects in view 1 provide, in accordancewith my invention, universal shaft comprising in combination two shaftportions having respective inner ends splined to one another so that theportions are nonrotatable though axially displaceable relative to oneanother, the surface material of at least one of the shaft portions atthe splined connections between the shaft portions having relativelygood antifriction and wearing properties; sealing means surrounding thesplined shaft portions and enclosing a lubricant-filled inner chamberfor the splined connection, the sealing means including a sealing ringand a scraper ring located adjacent and coaxial to one another, thescraper ring having a scraping end facing outwardly and being scrapinglyin engagement with one of the shaft portions; and a permanentlylubricated swivel joint carried by each of the shaft portions atrespective outer ends thereof.

In the universal shaft of the type of my invention, the interior of thesplined connection and the lubricant storage spaces of the swivel jointsrequire only a single filling with lubricant which lasts for the entireworking life of the shaft.

The result of providing at least the surface of one of the shaftportions at the splined connection between the shaft portions withrelatively good antifriction and wearing properties, such as by coatingthe splined teeth of the universal shaft with a plastic material such asnylon, for example, or by hardening the splined teeth by an inductiveprocess or by soft nitriding, for example, reduces wear of the splinedconnection while minimizing lubricant consumption andensuringsatisfactory emergency operating properties. These properties ofthe splined teeth are of great importance because, after the universalshaft joint has been in operation for a relatively long time, thequantity of lubricants previously supplied thereto may have decreased tosuch an extent that it would be inadequate to lubricate the splinedteeth treated in any other manner.

The scraper ring according to my invention serves to push away from thesurface of one of the shaft portions the bulk of the dirt accumulatedthereon, so that the sealing ring proper of the invention always slideson a smooth precleaned surface. The scraper ring also protects thesealing ring from other damaging external effects.

In accordance with a further feature of the invention and in order toeffect a relatively good sealing of the universal shaft, the sealingring is formed with a substantially square-shaped cross section. Such asealing ring having a substantially square cross section is provided inaccordance with my invention with a sealing lip at each comer of thesquare cross section, and a recess is provided at each lateral edge ofthe square cross sectron.

In accordance with another feature of the invention and in order toprovide a maintenance-free embodiment of the swivel joints, the swiveljoints are universal joints having spider members supported by means ofcup-shaped bearing bushings on fork arms of the swivel joints, alubricant chamber being located at the center of each of the spidermembers, the lubrinicating through a respective lubricating channel witha respective bearing space for the spider members. When the spidermembers of the swivel universal joints are assembled. the lubricantchamber is filled with the lubricant and then sealed by the closuremember which is, for example, secured by adhesive therein. The lubricantchamber is provided with sufficient vacuum for receiving lubricant in aquantity adequate for lubricating the universal joint pivot pin bearingsfor the entire servicable life of the joint so as to eliminate thenecessity for the maintenance thereof.

In accordance with an added feature of the invention l provide floatingend plates formed with lubricant pockets on both sides thereof andconsisting of a heat-stabilized, highly crystalline and heat-resistantplastic material through which the pivot pins of each of the spidermembers of the universal joints bears on the bases of the cup-shapedbearing bushings. By means of this type of pivot pin mounting, theheretofore frequent freezing of the faces of the pivot pin and the baseof the bushings is precluded. This feature thereby contributes towardsmaintenance-free construction of the universal shaft.

Due to the exceptionally good sealing action produced by the means forsealing the splined connection, the air pressure in the space closed bythe two shaft portions may become excessive when the two shaft portionsare slid together or telescoped.

Consequently, in accordance with an additional feature of my inventionand in order to obviate this disadvantage, l provide a central air ventpassage one of the portions of the shaft and disposed coaxial to therespective shaft portions. Because the air vent passage is coaxial tothe respective shaft portions and furthermore because of centrifugalforces arising during operation of the universal shaft, the lubricant inthe lubricant chamber is flung radially outwardly and cannot escapethrough the air vent passage, more particularly, if the lubricant ispreferably for a grease employed preferablyfor lubricating the splinedconnection and the pivot pin bearings.

Other features which are considered as characteristic for the inventionare set forth in the appended claims.

Although the invention is illustrated and described herein as embodiedin universal shaft, it is nevertheless notintended to be limited to thedetails shown, since various modifications and structural changes may bemade therein without departing from the spirit of the invention andwithin the scope and range of equivalents of the claims.

The construction and method of operation of the invention, however,together with additional objects and advantages thereof will be bestunderstood from the following description of the embodiment of theinvention when read in connection with the accompanying single FIGURE ofthe drawing showing in longitudinal view and in half section theuniversal shaft of my invention.

Referring now to the drawing, there is shown an universal shaftaccording to my invention formed of two coaxial parts 1 and 2 carryingat the outer ends thereof respectively a swivel joint 3, 4. The part 1formed as a shaft portion 5 of solid construction at the inner endthereof, and the part 2 is formed as a hollow shaft portion 6 at theinner end thereof. The shaft portions 5 and 6 engage with one another bymeans of a splined connection or joint 7, the shaft portion 5constituting the inner member of the splined connection and the hollowshaft portion 6 constituting the outer member of the splined connection.As can be readily seen from the figure, the splining permits relativeaxial movement of the shaft portions 5 and 6 but prevents relativerotation therebetween.

In the part 1 of the universal shaft, a collar 8 having a diametergreater than the outer diameter of the hollow shaft portion 6 in thevicinity of the splining 7 fonns a transition between the solid shaftportion 5 and the swivel joint 3. A sheet metal sleeve 10 is secured bya weld 9 to the collar 8 and carries at the free end thereof an annularsealing casing II. The sealing casing 11 is fonned at the radially innerside thereof with an annular groove having a rectangular cross seccantchamber being sealed by a closure member and commution, and a sealingring 12 of substantially square cross section is seated within theannular groove. The sealing ring 12 is of the type aforementionedwherein the corners of the squareshaped cross section thereof are formedwith sealing lips and a recess is formed in each of the lateral edges ofthe square. The sealing casing 11 is formed with an additional annularrecess separated by a radially extending wall 13 from the annular groovein which the sealing ring 12 is located. In the additional annularrecess there is received a scraper ring 14 having substantially the sameouter and inner diameters as those of the sealing ring 12. The radiallyinner sealing lips of the rings i2 and 14 cooperate with and slidinglyengage an outer peripheral surface 15 of the hollow shaft portion 6located in the vicinity of the splining 7. The sealing ring l2 and thescraper ring 14 serve to seal off a chamber 16 formed by the assembly ofthe parts 1 and 2 and located between the sleeve and the solid shaftportion 5 and including the interior of the hollow shaft portion 6, thechamber 16 being filled with a lubricating grease. If this lubricatingchamber 16 were to have been completely sealed off from the surroundingatmosphere upon assembly of the parts 1 and 2 of the universal shaft,the pressure therein would have become excessive; accordingly, an airvent passage 17 is bored coaxially through a welding pin 18 to which thehollow shaft portion 6 is welded. The air vent passage 17 extendsthrough a fork foot of the universal swivel joint 4, which is of unitaryconstruction with the welding pin 18, so that the air vent passage 17communicates with the outer atmosphere.

To eliminate the requirement for servicing of the universal swiveljoints 3 and 4, they are provided with a construction describedhereinafter only with regard to the swivel joint 3. It is obvious, ofcourse, that the swivel joint 4 is of similar construction. As shown inthe figure, the swivel joint 3 is provided with a spider member 20 whichbeats with the bearing pins 21 thereof through needle bearings 22 andcup-shaped bearing bushings 23 in fork arms 24 of the swivel joint 3.

In order to axially fix the spider member 20, end plates or discs 25,formed on both sides thereof with lubricating grooves, are disposedbetween the end faces of the spider member 20 and the bases of thebearing bushings 23. A contact seal 27 protected by a metal ring 26 isprovided at the open end of each of the cup-shaped bearing bushings. Arecess 28 forming a lubricant chamber is located at the center of thespider member 20 and is closed by a cylindrical cup-shaped cover member29. The cylindrical wall of the cup-shaped cover member 29 resilientlyabuts an inner peripheral wall surface of a recess 30 which surroundsthe recess 28 and is secured therein by a curable or hardenableadhesive.

Bore passages 3i extend through the bearing pins 21 radially outwardlyfrom the central recess 28 and connect the recess 28 to the bearingsurfaces of the swivel joint 3. A filling screw 32 is provided in thecenter of the base of at least one of the bearing bushings 23 andcooperates with the respective passage 31 for filling the lubricatingchamber formed by the recess 28 with lubricant.

Reference can be had to my copending application Ser. No. 862,268, 268,filed Sept. 30, 1969, for further details regarding a universal jointspider member of the type generally shown and described herein.

lclaim:

1. Universal shaft comprising in combination two shaft portions havingrespective inner ends splined to one another so that said portions arenonrotatable though axially displaceable relative to one another, thesurface material of at least one of said shaft portions at the splinedconnections between said shaft portions having relatively goodantifriction and wearing properties; sealing means surrounding saidsplined shaft portions and enclosing a lubricant-filled inner chamberfor said splined connection, said sealing means including a sealing ringand a scraper ring having located adjacent and coaxial to one another,said scraper ring having a scraping end facing outwardly and beingscrapingly in engagement with one of said shaft portions; and apermanently lubricated swivel joint carried by each of said shaftportions at respective outer ends thereof, said swivel oints beinguniversal oints each comprising a fork arm, cup-shaped bearing bushingscarried by said fork arm, and a spider member supported on said fork armby said cup-shaped bearing bushings, each spider member being providedwith pivot pins, and including floating end plates formed with lubricantpockets on both sides thereof and consisting of a heat-stabilized highlycrystalline and heat-resistant plastic material, said pivot pins bearingthrough said floating end plates against the bases of said cup-shapedbearing bushings.

2. Universal shaft according to claim 1 wherein the surface material ofsaid one shaft portion is inductively hardened at the splinedconnection.

3. Universal shaft according to claim 1 wherein the surface material ofsaid one shaft portion is softly nitrided at the splined connection.

4. Universal shaft according to claim 1 wherein the surface material inthe form of a coating on said one shaft portion at the splinedconnection.

5. Universal shaft according to claim 4 wherein said plastic material isnylon.

6. Universal shaft according to claim 1 wherein said sealing ring has asubstantially square cross section.

7. Universal shaft according to claim 9 including. a lubricant chamberlocated at the center of each of said spider members, said lubricantchamber being sealed by a closure member and communicating through alubricating channel with a bearing space for the respective spidermember.

8. Universal shaft according to claim 7 wherein said lubricant chamberhas an opening surrounded by a recess, said closure member comprising acover force-lockingly and formlockingly received in said recess.

9. Universal shaft according to claim 1 wherein one of said shaftportions is formed with a central air vent passage.

1. Universal shaft comprising in combination two shaft portions havingrespective inner ends splined to one another so that said portions arenonrotatable though axially displaceable relative to one another, thesurface material of at least one of said shaft portions at the splinedconnections between said shaft portions having relatively goodantifriction and wearing properties; sealing means surrounding saidsplined shaft portions and enclosing a lubricant-filled inner chamberfor said splined connection, said sealing means including a sealing ringand a scraper ring having located adjacent and coaxial to one another,said scraper ring having a scraping end facing outwardly and beingscrapingly in engagement with one of said shaft portions; and apermanently lubricated swivel joint carried by each of said shaftportions at respective outer ends thereof, said swivel joints beinguniversal joints each comprising a fork arm, cupshaped bearing bushingscarried by said fork arm, and a spider member supported on said fork armby said cup-shaped bearing bushings, each spider member being providedwith pivot pins, and including floating end plates formed with lubricantpockets on both sides thereof and consisting of a heat-stabilized highlycrystalline and heat-resistant plastic material, said pivot pins bearingthrough said floating end plates against the bases of said cup-shapedbearing bushings.
 2. Universal shaft according to claim 1 wherein thesurface material of said one shaft portion is inductively hardened atthe splined connection.
 3. Universal shaft according to claim 1 whereinthe surface material of said one shaft portion is softly nitrided at thesplined connection.
 4. Universal shaft according to claim 1 wherein thesurface material in the form of a coating on said one shaft portion atthe splined connection.
 5. Universal shaft according to claim 4 whereinsaid plastic material is nylon.
 6. Universal shaft according to claim 1wherein said sealing ring has a substantially square cross section. 7.Universal shaft according to claim 9 including a lubricant chamberlocated at the center of each of said spider members, said lubricantchamber being sealed by a closure member and communicating through alubricating channel with a bearing space for the respective spidermember.
 8. Universal shaft according to claim 7 wherein said lubricantchamber has an opening surrounded by a recess, said closure membercomprising a cover force-lockingly and form-lockingly received in saidrecess.
 9. Universal shaft according to claim 1 wherein one of saidshaft portions is formed with a central air vent passage.